[BOT-X]: add aliases to commands

[tiagojpdias]

Description

This pull request aims to provide commands with aliases to make it more versatile. Also improved the reaction to private messages extracting that behavior to an helper, avoiding repetition.

Task items:

• [X] Add react helper;
• [X] Add aliases property to !acronimo;
• [X] Print aliases when displaying command usage;
• [X] Check for command name or aliases when receiving a message;
• [X] Add react and printAliases tests;